Measuring IQ in an autistic person is sometimes quite difficult to do accurately using the standard measurement instruments. When attempting to find out whether a person who has autism is ‘high functioning’ or ‘low functioning’ based on an IQ score then care should be taken for the above reason. A misleadingly low score can be measured if a person with autism takes a test that contains a large amount of language processing or a large quantity of verbal instructions or even ‘non-verbal’ portion of standard intelligence can lead to a low score. When comparing standard testing methods and the truly non-verbal method for example the Leiter-R, there can be a very significant difference between that of an autistic person’s IQ score.
There is a diagnosis of very high-functioning autism that exists in either the DSM-IV-TR or the ICD-10. These both have diagnoses of autistic disorder and childhood autism similarly. Analogous of the high-functioning when applied to the condition known as schizophrenia and some other physical disorders. The common term known as high-functioning autism, was started out as a short hand term that describes people who are diagnosed autistic, who could never the less speak and carry on with many simple and complex day-to-day activities like eating and dressing themselves for example. Low-functioning is the other term used. It was the complete opposite of high-functioning. High-functioning autism was then labeled as a quasi-diagnostic itself by researchers who had being researching autism. This was also common with low-functioning autism, and some of the time Asperger’s Syndrome, which would distinguish relative levels of adaptation and development. Autistic spectrum challenge that a simple definite division in the low-functioning and high-functioning creates an illusive division, believe many people. Instead they would much rather prefer to see the spectrum as multidimensional, with lots of autistic personalities changeable in intensity and often changing day by day. For example, Asperger’s syndromes definition as fundamentally, autism without speech or any other cognitive delays would create an arbitrary wall in a very common condition, is what they believe would happen.